DESCRIPTION:(provided by applicant): A multidisciplinary investigation is proposed to examine the influence of aerobic fitness on the neurocognitive function in older adults. More specifically, we plan to investigate the relationship between aerobic fitness, cognitive function and brain function and structure. Our preliminary data as well as that of others suggests that improvements in aerobic fitness have selective rather than general effects on cognitive function. That is, improvements in aerobic fitness appear to result in improvements in executive control process such as scheduling, planning, coordination, inhibition, and working memory. Neuroimaging and human lesion data further suggest that such processes are supported, to a large extent, by frontal and prefrontal regions of cortex. Indeed, executive control processes and the prefrontal and frontal regions that support them have shown substantial and disproportionate age-related declines. The main hypothesis that we test in the present project is that such deficits may be moderated by improvements in aerobic fitness. We will investigate the relationship between aerobic fitness, cognitive function, and brain function and structure with cross-sectional studies. In these studies 40 high fit old adults, 40 low fit old adults (60 to 75 years) and 40 young adult controls will be assessed in terms of (a) fitness level, (b) performance on a battery of neurocognitive tasks and (c) functional and structural measures of brain integrity and activation using MRI and event-related fMRI. Measures of brain activation will be collected as subjects perform a number of neurocognitive tasks. Our hypotheses are as follows. First, we predict differences in performance and fMRI activation between high and low fit adults on executive control processes and the brain regions that support them. We do not expect to observe substantial fitness differences on non-executive processes or non-frontal activation patterns. Second, we predict structural differences in prefrontal and frontal regions of cortex between the low and high fit old adults. Third, we predict that performance and brain structure and function, particularly on the executive control processes and the cortical regions which support them, of the high fit older adults will approach that of the young adult control subjects.